摘要:

AbstractEs wurde eine kinetische Untersuchung über die Polykondensation von niedermolekularem Polyäthylenterephthalat in Anwesenheit des Katalysator‐Inhibitor‐Systems Mn(OAc)2‐Triphenylphosphat‐Sb2O3durchgeführt. Festgestellt wurde, daß für niedrige Konzentrationen des Katalysators bis zu 2,5 · 10−4mol/mol Monomeres die Polykondensation bei den vier untersuchten Temperaturen 270, 280, 285 und 290°C als Reaktion zweiter Ordnung verläuft. für Konzentrationen von 3,0 und 3,5·10−4mol/mol bei 285 und 290°C ändert sich die Reaktionsordnung infolge von Abbauprozessen. Die Geschwindigkeitskonstanten erhalten praktisch bedeutende Werte bei 280°C für Katalysatorkonzentrationen von 3,0 und 3,5 · 10−4mol/mol sowie bei 285 und 290°C und Katalysatorkonzentrationen

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550101

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractRates of sodium bisulfite initiated polymerization of methyl methacrylate (MMA) in water medium were determined in absence and in presence of graphite or silicon. The effect of graphite as well as of silicon on the overall rate of polymerization at 40°C was measured. Overall rates of polymerization increased in presence of graphite from 2.3 × 10−5to 8.7 × 10−5mol·1−1·s−1when its concentration was varied from 0 to 5g·l−1, and to 5.6 × 10−5mol·l−1·s−1as the silicon concentration was varied from 0 to 16 g·l−1. Beyond these concentrations of graphite and silicon, the overall rate of polymerization began to decrease.The overall rate was found to increase with increase of monomer concentration in case of graphite and in case of silicon with the difference that the increase in case of silicon is limited.Mild shaking was found to increase the rate of polymerization.Raising the temperature from 30°C to 60°C increased the overall rate from 2.6 × 10−5to 9.3 × 10−5mol·l−1·s−1when using a small amount of silicon (3 g·l−1) while the increase was from 3.7 × 10−5to 11.0 × 10−5mol·l−1·s−1when using the same concentration of graphite. Increasing the initiator concentration resulted in a limited increase in the overall rate. The number average molecular weights of the obtained polymers were found to d

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550102

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe membrane performance of aqueous polymer solutions using porous cellulose acetate membranes is investigated by changing the membrane preparation methods and the permeation conditions. It is found that the rate of water permeability decreases with an increase in the evaporation period using pure water as feed, but the permeation rate is almost constant regardless of the evaporation period using 1.0% aqueous solution of poly(vinyl alcohol) as feed. This phenomenon is attributable to the concentration polarization of poly(vinyl alcohol) molecules onto the membrane surface. The membrane performance is improved by adding some additives to the casting solutions and by treating with certain solutions. The permeation rate decreases with an increase in the feed concentration at a given operating pressure but the solute separation is always 100%, regardless of the feed concentration in the range of 0.5 to 5.0% aqueous solution of the membrane compaction and poly(vinyl alcohol). These phenomena are explained on the basic of the osmotic pressure, the feed viscosity, and the concentration polarization. The permeation rate is constant regardless of the operating pressure. This result is discussed on the basis of the concentration polarization. From comparing the permeation characteristics of aqueous solutions of poly(vinyl alcohol) and poly(ethylene glycol), it is seen that there are differences of the form of polymer molecules in solution and complex interactions between polymer molecules and membrane substrate. The behaviour of polymer solutes and membranes during the concentration of aqueous solutions of polymers is discussed.

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550103

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractHochdruck‐Polyäthylen reagiert in Gegenwart von Radikalbildnern mit Maleinsäureanhydrid (MSA) unter Einbau von Anhydridgruppen ohne Aufpfropfung oder Entstehung von homopolymerem MSA. Die Versuchsbedingungen werden angegeben; am Beispiel der Umsetzung des erhaltenen Polymeren mit n‐Butylamin wird die Reaktivität der eingebauten Anhydridgruppen g

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550104

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractFor the purpose of application in artificial kidneys the permeation characteristics of semipermeable membranes obtained from a system of cellulose nitrate/methyl alcohol/1,4‐dioxane/barium perchlorate were investigated under various conditions. The optimum composition of the casting solution was found to be the proportion cellulose nitrate: methyl alcohol: 1,4‐dioxane as 13:45:42 (wt.‐%). It was found that the permeation rate was influenced by the evaporation period, the maximum permeability lay at 30s. The addition of barium perchlorate to the casting solution increased the permeation rate, especially if more than 60 wt.‐% of barium perchlorate per cellulose nitrate was used. The permeation rate is increasing with the operating pressure, but decreasing with the feed concentration. When several samples of poly(ethylene glycol) having different average molecular weights were used as feed solute, the permeation rate decreased with an increase in average molecular weight. The permeation fraction was 100% in systems of poly(ethylene glycol) with mol. wt. from 200 to 4000 and was 0% in systems of poly(ethylene glycol) 6000 under 200 mm Hg. In blood filtrations the permeation rate of cellulose nitrate membranes had about four‐fold values of cuprophane membranes, and moreover no protein was found in the blood

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550105

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractImide‐containing polyesters have been prepared by melt polycondensation of propylene glycol with saturated and/or unsaturated diacids and imide diacids. These imide diacids have been synthesized from trimellitic anhydride and aliphatic ω‐amino acids, and differ from each other in the number of CH2groups.When mixtures of styrene and the unsaturated polyester imides are activated by peroxidic type initiators, crosslinked products are obtained, the properties of which can be related to the proportion of imide rings and the length of the aliphatic chain in its chemical s

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550106

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractEight imide‐diacids were synthesized from trimellitic anhydride, pyromellitic anhydride and aminoacids of the formula HOOC(CH2)nNH2, with n = 1,2,3,5. From them, polyanhydride‐imides were obtained following a general method of formation of polyanhydrides in the presence of acetic anhydride1,2.These co‐polyimides have an aliphatic‐aromatic structure and the relation between the general properties and the amount of the aliphatic part in the repeat unit was studied. IR spectroscopy, elemental analysis and viscosity measurements were used for the characterization. Studies of solubility, hydrolysis resistance and thermal properties wer

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550107

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractL'examen du comportement rhéologique à l'état fondu de mélanges à base de polybutène‐1 et de polypropène a été effectué en fonction de la température, de la contrainte de cisaillement et de la vitesse de cisaillement. Les courbes de variations de la viscosité apparente en fonction de la composition présentent un minimum qui correspond approximativement à un maximum des courbes de variation du facteur de Barus. Ces résultats semblent montrer que le domaine de faible viscosité soit associé à un domaine de forte élasticité pour les matériaux vi

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550108

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe cohesive energy densities (c.e.d.) of copolymers having varying compositions of 2‐hydroxyethylmethacrylate (HEMA) and methylacrylate (MA) were determined from swelling measurements. It was found that the c.e.d. decreases as the 2‐hydroxyethylmethacrylate content increases in the copoly

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550109

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractDurch Initiierung mit Aluminiumsesquichlorid wurden partiell alternierende Terpolymere aus α‐Methylstyrol, Butadien und Methacrylnitril dargestellt. Die Kettenstruktur der Terpolymeren wurde durch13C‐NMR‐Spektroskopie be

ISSN:0003-3146    

DOI:10.1002/apmc.1976.050550110

出版商:Hüthig&Wepf Verlag    

年代:1976

数据来源: WILEY